The assignee of the present invention designs and manufactures spacecraft for communications and broadcast services. The spacecraft are carried into space, into a transfer or operational orbit, for example, by a launch vehicle. Structures of such spacecraft commonly include a structural interface ring (the “payload launch vehicle adapter structure”) or other load bearing structure which mates to an adapter ring or other load bearing structure or dispenser associated with the launch vehicle.
An example of a known technique for interfacing a payload to a launch vehicle is illustrated in FIG. 1A. In the illustrated example, a single spacecraft 110 is configured for launch on a launch vehicle 120. Launch vehicle 120 includes a payload fairing 121 and launch vehicle payload interface ring 125. Spacecraft 110 has a payload launch vehicle adapter structure 115 that detachably mates to the launch vehicle payload interface ring 125.
It is often desirable to configure two or more spacecraft for simultaneous launch on the same launch vehicle. Conventional stacked dual-launch configurations are illustrated in FIG. 1B and FIG. 1C. Because many conventional spacecraft have a cube-like form factor, a natural conventional dual launch configuration contemplates stacking one spacecraft on top of the other. This approach may provide an advantage of splitting the launch vehicle cost while more fully utilizing available payload fairing volume. In the configuration illustrated in FIG. 1B, the lower spacecraft 110(1) supports the upper spacecraft 110(2) during launch. In the configuration illustrated in FIG. 1C, a dual payload carrier 126 may be provided, as disclosed, for example, in U.S. Pat. No. 7,832,687, thereby alleviating the need for the lower spacecraft 110(1) to provide load bearing support for the upper spacecraft 110(2) but necessitating the cost, mass and complexity of the dual payload carrier.
A characteristic feature of the above described techniques is that launch acceleration loads are substantially orthogonal to an interface plane at which the payload launch vehicle interface ring and the launch vehicle payload interface ring are joined. Moreover, it will be appreciated that a central axis of the interface rings is coaxial with the launch vehicle longitudinal axis.
In alternative known arrangements, multiple spacecraft may be launched on a common launch vehicle in the configurations illustrated in FIGS. 1D and 1E, for example. Referring first to FIG. 1D, an arrangement is illustrated wherein eight auxiliary payloads 111 may be launched together with a primary payload, spacecraft 110(1). It will be appreciated that in such a configuration, as illustrated, the auxiliary payloads 111(1) through 111(8) must be a small fraction of the mass and envelope of spacecraft 110(1). Referring now to FIG. 1E, an example of another known arrangement is illustrated wherein multiple spacecraft are supported by a common adapter structure 126, which may be referred to as a “dispenser”. It will be appreciated that, in the illustrated configuration, launch acceleration loads are substantially parallel to an interface plane at which each spacecraft interfaces to the common adapter structure. As a result, spacecraft 112(1)-112(4) are cantilevered with respect to the launch acceleration loads.
It is desirable to find improved arrangements whereby two or more spacecraft may be accommodated within a single payload fairing while the disadvantages noted above are reduced.